For convenience, certain terms that are repeated throughout the present specification are defined below:
(a) Inter-CD defines the compositional variation, in terms of ethylene content, among polymer chains. It is expressed as the minimum deviation (analogous to a standard deviation) in terms of weight percent ethylene from the average ethylene composition for a given copolymer sample needed to include a given weight percent of the total copolymer sample which is obtained by excluding equal weight fractions from both ends of the distribution. The deviation need not be symmetrical. When expressed as a single number, for example 15% Inter-CD, it shall mean the larger of the positive or negative deviations. For example, for a Gaussian compositional distribution, 95.5% of the polymer is within 20 wt.% ethylene of the mean if the standard deviation is 10%. The Inter-CD for 95.5% wt.% of the polymer is 20 wt.% ethylene for such a sample. PA1 (b) Intra-CD is the compositional variation, in terms of ethylene, within a copolymer chain. It is expressed as the minimum difference in weight (wt.) % ethylene that exists between two portions of a single copolymer chain, each portion comprising at least 5 weight % of the chain. PA1 (c) Molecular weight distribution (MWD) is given a measure of the range of molecular weights within a given copolymer sample. It is characterized in terms of at least one of the ratios of weight average to number average molecular weight, M.sub.w /M.sub.n, and Z average to weight average molecular weight, M.sub.z /M.sub.w, where ##EQU1## Ni is the number of molecules of weight Mi. PA1 (a) at least one copolymer having at least M.sub.w /M.sub.n less than 2 and a M.sub.z /M.sub.w less than 1.8; and PA1 (b) at least one plastic composition. Preferably, the at least one copolyme has M.sub.w /M.sub.n less than 1.4 and M.sub.z /M.sub.w less than 1.3. PA1 (a) an ethylene-alpha olefin copolymer; PA1 (b) one or more plastic compositions; and PA1 (c) at least one copolymer, in an amount equal to approximately 80 wt. % or less of the composition, comprising a plurality of Ziegler-Natta catalyzed polymer chains, substantially each of said chains being end capped with at least one functional group-containing unit which is otherwise essentially absent from said copolymer chains, said functional group being incorporated in a polymer selected from the group consisting of: ##STR1## the monomers thereof, and the mixtures thereof; wherein R.sub.1 through R.sub.4 are hydrocarbons with 1-30 carbon atoms seleced from the group consisting of saturated or unsaturated, branched or unbranched, aliphatic, aromatic, cyclic, or polycyclic hydrocarbons, wherein R.sub.5 is the same as R.sub.4 but may additionally be hydrogen; and wherein x=1-10,000. PA1 (a) at least one copolymer which comprises a plurality of copolymer chains, substantially each comprising: PA1 said second segment constituting less than 50 percent by weight of said copolymer chain, said second segment being in the form of one contiguous segment or a plurality of discontinuous segments; PA1 said at least one halogen-containing monomer being cross-linkable under conditions which do not cross-link said first segment to any substantial extent; and PA1 (b) at least one plastic composition. PA1 (a) at least one copolymer consisting essentially of a plurality of copolymer chains having at least one of M.sub.n /M.sub.n less than 2 and M.sub.z /M.sub.w less than 1.8, said copolymer comprising ethylene, an alpha-olefin, and at least one halogen-containing monomer selected from the group consisting of: PA1 A. A nodule region of substantial cross-linking of copolymer chain second segments substantially cross-linked by at least one cross-linking agent, substantially each of said second segments comprising a copolymer of ethylene, an alpha-olefin, and at least one halogen-containing monomer selected from the group consisting of: PA1 B. substantially uncross-linked copolymer chain first segments extending therefrom, substantially each of said first segments comprising a copolymer of ethylene and an alpha-olefin; PA1 (a) in at least one mix-free reactor; PA1 (b) with essentially one active catalyst species; PA1 (c) using at least one reaction mixture which is essentially transfer-agent free; PA1 (d) in such a manner and under conditions sufficient to initiate propagation of essentially all of said copolymer chains simultaneously, wherein chains of said at least one copolymer are dispersed within the reaction mixture. PA1 (a) olefinic chlorosilane of the formula EQU SiRR.sub.x 'Cl.sub.3-x PA1 wherein; PA1 (b) olefinic hydrocarbon halide of the formula RR'X wherein; PA1 (i) a first copolymer having at least one of M.sub.w /M.sub.n less than 2 and M.sub.z /M.sub.w less than 1.8; and PA1 (ii) a second copolymer having both M.sub.w /M.sub.n greater than or equal to 2 and M.sub.z /M.sub.w greater than or equal to 1.8; may be prepared for incorporation into the composition of the invention by forming the first polymer by the previously described process, reacting a second reaction mixture to produce the second copolymer, and then blending the first and second copolymers to form the elastomer for use with the composition of the invention. Subsequently, this elastomer is blended with one or more plastic compositions to form the composition of the invention. PA1 a. straight chain acyclic dienes such as: 1,4-hexadiene; 1,6-octadiene; PA1 b. branched chain acyclic dienes such as: 5-methyl-1,4-hexadiene; 3,7-dimethyl-1,6-octadiene; 3,7-dimethyl-1,7-octadiene and the mixed isomers of dihydromyrcene and dihydroocimene; PA1 c. single ring alicyclic dienes such as: 1,4-cyclohexadiene; 1,5-cyclooctadiene; and 1,5-cyclododecadiene; PA1 d. multi-ring alicyclic fused and bridged ring dienes such as: tetrahydroindene; methyltetrahydroindene; dicyclopentadiene; bicyclo-(2,2,1)-hepta-2,5-diene; alkenyl, alkylidene, cycloalkenyl and cycloalkylidene norbornenes such as 5-methylene-2-norbornene (NMB), 5-ethylidene-2-norbornene (ENB), 5-(4-cyclopentenyl)-2-norbornene; 5-cyclohexylidene-2-norbornene. PA1 a. the catalyst system produces essentially one active catalyst species; PA1 b. the reaction mixture is essentially free of chain transfer agents; and PA1 c. the polymer chains are essentially all initiated simultaneously, which is at the same time for a batch reactor, or at the same point along the length of the tube for a tubular reactor. PA1 (a) in at least one mix-free reactor, PA1 (b) using a catalyst system that produces essentially one active catalyst species, PA1 (c) using at least one reaction mixture which is essentially transfer agent-free, and PA1 (d) in such a manner and under conditions sufficient to initiate propagation of essentially all polymer chains simultaneously. PA1 (a) a compound of a transition metal, i.e., a metal of Groups I-B, III-B, IV-B, VI-B, VII-B, and VIII of the Periodic Table, and PA1 (a) in at least one mix free reactor, PA1 (b) using catalyst systems such that each component or mode in a MWD is produced by essentially one active catalyst species, PA1 (c) using at least one reaction mixture which is essentially transfer agent-free, and PA1 (d) in such a manner and under conditions sufficient to initiate propagation of essentially all polymer chains made with a particular catalyst species simultaneously. PA1 (1) In a single mix free reactor operated as described above, portions of the polymer product can be withdrawn after varying times in a batch reactor or at varying distances along a tubular reactor representing different average molecular weights and these portions can be blended. PA1 (2) Mix-free reactors can be operated either in parallel or sequentially and the products blended. PA1 (3) Two or more catalysts that form narrow MWD polymer of differing molecular weight can be added at the onset of polymerization in a mix-free reactor. Each catalyst must meet the requirements of minimizing chain transfer and initiating simultaneous propagation of all the chains produced by that catalyst. PA1 (4) A catalyst system that generates multiple active catalyst species can be added at the start of the polymerization. Each catalyst species produced must give simultaneous chain initiation and minimize chain transfer. PA1 (5) Additional catalyst and monomer, if desired, can be added at varying lengths along a tubular reactor, or times in a batch reactor, to initiate the formation of additional MWD modes. The catalysts can be the same or different, as long as chains are initiated simultaneously and chain transfer is minimized. PA1 (6) For catalyst systems that show a decay in activity as a function of time due to deactivation, catalyst reactivator can be added during the course of the polymerization to regenerate the dead catalyst and form a new mode of narrow MWD copolymer. PA1 (a) in at least one mix-free reactor, PA1 (b) using a catalyst system that produces essentially one active catalyst species, PA1 (c) using at least one reaction mixture which is essentially transfer agent-free, and PA1 (d) in such a manner and under conditions sufficient to initiate propagation of essentially all polymer chains simultaneously. PA1 (a) in at least one mix-free reactor, PA1 (b) using a catalyst system that produces essentially one active catalyst species, PA1 (c) using at least one reaction mixture which is essentially transfer agent-free, and PA1 (d) in such a manner and under conditions sufficient to initiate propagation of essentially all polymer chains simultaneously. PA1 (a) straight chain acyclic dienes such as: 1,4-hexadiene; 1,6-octadiene; PA1 (b) branched chain acyclic dienes such as: 5-methyl-1, 4-hexadiene; 3,7-dimethyl-1, 6-octadiene; 3,7-dimethyl-1, 7-octadiene and the mixed isomers of dihydromyrcene and dihydroocimene; PA1 (c) single ring alicyclic dienes such as: 1,4-cyclohexadiene; 1,5-cyclooctadiene; and 1,5-cyclododecadiene; PA1 (d) multi-ring alicyclic fused and bridged ring dienes such as: teetrahydroindene; methyltetrahydroindene; dicyclopentadiene; bicyclo-(2,2,1)-hepta-2,5 diene; alkenyl, alkylidene, cycloalkenyl and cycloalkylidene norbornenes such as 5-methylene-2norbornene (MNB), 5-ethylidene-2-norbornene, 5-(4-cyclopentenyl)-2-norbornene; and 5-cyclohexylidene-2-norbornene. PA1 (i) R is a Ziegler copolymerizable olefin; PA1 (ii) R' is a hydrocarbon with 1-30 carbon atoms selected from a group consisting of the saturated or unsaturated as well as branched or unbranched aliphatic aromatic, cyclic, and polycyclic hydrocarbons; and PA1 (iii) X is a halogen. Then preferred olefinic hydrocarbon halides are 5-parachloromethyl phenyl-2-norbonene and 5-chloromethyl-2-norbonene. PA1 (a) in at least one mix-free reactor, PA1 (b) using a catalyst system that produces essentially one active catalyst species, PA1 (c) using at least one reaction mixture which is essentially transfer agent-free, and PA1 (d) in such a manner and under conditions sufficient to initiate propagation of essentially all polymer chains simultaneously.
Ethylene-propylene copolymers, particularly elastomers, are important commercial products. Two basic types of ethylene-propylene copolymers are commercially available. Ethylene-propylene copolymers (EPM) are saturated compounds requiring vulcanization with free radical generators such as organic peroxides. Ethylene-propylene terpolymers (EPDM) contain a small amount of non-conjugated diolefin, such as dicyclopentadiene, 1,4-hexadiene, or ethylidene norbornene, which provides sufficient unsaturation to permit vulcanization with sulfur. Such polymers that include at least two monomers, i.e., EPM and EPDM, will hereinafter be collectively referred to as copolymers.
These copolymers have outstanding resistance to weathering, good heat aging properties and the ability to be compounded with large quantities of fillers and plasticizers, resulting in low cost compounds which are particularly useful in automotive and industrial mechanical good applications. Typical automotive uses are in tire sidewalls, inner tubes, radiator and heater hose, vacuum tubing, weather stripping and sponge doorseals, and as Viscosity Index (V.I.) improvers for lubricating oil compositions. Typical mechanical goods uses are for appliance, industrial and garden hoses, both molded and extruded sponge parts, gaskets and seals, and conveyor belt covers. These copolymers also find use in adhesives, appliance parts, as in hoses and gaskets, wire and cable, and plastics blending.
The efficiency of peroxide curing depends on composition. As the ethylene level increases, it can be shown that the "chemical" crosslinks per peroxide molecule increase. Ethylene content also influences the rheological and processing properties, because crystallinity, which acts as physical crosslinks, can be introduced. The crystallinity present at very high ethylene contents may hinder processibility, and may make the cured product too "hard" at temperatures below the crystalline melting point to be useful as a rubber.
As can be seen from the above, based on their respective properties, EPM and EPDM find many, varied uses. It is known that the properties of such copolymers which make them useful in a particular application are, in turn, determined by their composition and structure. For example, the ultimate properties of an EPM or EPDM copolymer are determined by such factors as composition, compositional distribution, sequence distribution, molecular weight, and molecular weight distribution (MWD).
It is well known that the breadth of the MWD can be characterized by the ratios of various molecular weight averages. One of such averages is the ratio of weight average to number average molecular weight (M.sub.w /M.sub.n). Another of the ratios is the Z average molecular weight to weight average molecular weight (M.sub.z /M.sub.w).
Copolymers of ethylene and at least one other alphaolefin monomer, including EPM and EPDM polymers, which are intramolecularly heterogeneous and intermolecularly homogeneous, and which have a narrow MWD, characterized as at least one of M.sub.w /M.sub.n less than 2 and M.sub.2 /M.sub.w less than 1.8, have improved properties in lubricating oil. Such copolymers are disclosed in COZEWITH et al., which is incorporated herein by reference. For convenience, such polymers are hereinafter referred to as narrow MWD copolymers. Copolymers having MWD with both M.sub.w /M.sub.n greater than or equal to 2 and M.sub.z /M.sub.w greater than or equal to 1.8 are hereinafter referred to as broad MWD copolymers.
It is generally recognized that the cure rate and physical properties of copolymers of ethylene and at least one other alpha-olefin monomer are improved as MWD is narrowed. Narrow MWD polymers have superior cure and tensile strength characteristics over such polymers having broader MWD. However, the advantages in physical properties gained from having a narrow MWD are sometimes offset by the poorer processability of such materials. They are often difficult to extrude, mill, or calendar. Nevertheless, is certain instances the narrow MWD copolymer is advantageous in plastics blending.
As to milling behavior of EPM or EPDM copolymers, this property varies radically with MWD. Narrow MWD copolymers crumble on a mill, whereas broad MWD materials will band under conditions encountered in normal processing equipment. Broader MWD copolymer has a substantially lower viscosity than narrower MWD polymer of the same weight average molecular weight.
Thus, there exists a continuing need for discovering polymers with unique properties and compositions. This is easily exemplified with reference to the area of blends of elastomers and plastics having various utilities.
Plastic-elastomer blends comprising a discontinuous phase of the elastomer dispersed within a continuous phase of the plastic find various uses, such as in battery cases. For such blends, an intimate dispersion of the elastomer discontinuous phase within the plastic composition continuous phase is a desirable property.
Blends comprising cocontinuous phases of plastic and elastomer tend to have greater impact strength than the pure plastic compositions, and are useful in such products as automobile bumpers.
It is highly desirable in plastic-elastomer blends, particularly the continuous-discontinuous phases blends, to attain a higher Gardner impact strength without a corresponding lowering of knit line toughness or stiffness.
U.S. Pat. No. 4,059,651 discloses a blend of 70-98 wt.% polypropylene, 2-30 wt.% EPDM elastomer, and halogenated phenol aldehyde resin present in an amount of about 1-20 parts per 100 parts of elastomer. The elastomer is disclosed as containing about 40-80 wt.% ethylene and about 2-12 wt.% diene with the balance being propylene. The components are mixed by conventional techniques and heated at above the melting point of the propylene, e.g., 300.degree.-400.degree. F. Alternatively, the halogenated phenol aldehyde resin may first be mixed with the polypropylene at these same temperatures, with the elastomer mixed in thereafter. After the mixing and heating, the blend may be molded.
U.S. Pat. No. 4,087,485 to Huff discloses a blend comprising about 2-20% by weight ethyelene-propylene copolymer elastomer, 70-90% by weight polypropylene, and about 1-15% by weight LDPE. The elastomer may further include a non-conjugated diene. The blend may be prepared by mixing with conventional equipment at 350.degree.-400.degree. F. for about 4-7 minutes, with conventional agents employed for curing.
U.S. Pat. No. 4,088,714 to Huff discloses a blend comprising 40-90 wt.% EPR, EPM, or EPDM copolymer, 14-20 wt.% cross-linkable low density polyethyelene, and less than 50 wt.% isotactic polypropylene. Three radical generating or cross-linking agents such organic peroxides are used to cross-link the elastomer and the cross-linkable low density polyethylene. Triallylcyanurate is employed to enhance the curing and increase resiliency, tensile strength, and impact strength.
U.S. Pat. No. 4,221,882 to Huff discloses blends comprising 45-67% polypropylene, 30-45% polyethylene, and 3.5-11% ethylene-propylene copolymer. The polypropylene and ethylene-propylene compolymer are premixed by conventional means and heated to about 204.degree. C. The pre-blend is then pelletized or powdered and mixed with virgin high density polyethylene, and melt-mixed as an extruder let down, normally at about 204.degree. C. The final blend is then employed for molding parts.
U.S. Pat. No. 4,251,646 to Smith, Jr. discloses a blend of 60-90% by weight polypropylene, 30-5% by weight thermoplastic crystalline heteroblock propylene-ethylene copolymer, and 30-5% ethylene-propylene copolymer. The blends are processed by conventional techniques at temperatures above 200.degree. C., are readily extrudable and moldable.
U.S. Pat. No. 4,375,531 to Ross discloses visbroken polymeric blends comprising a first component selected from a group consisting of block propylene-ethylene copolymers, reactormade intimate mixtures of polypropylene and randomly oriented copolymers of propylene and ethylene, and blends of propylene and randomly oriented copolymers of propylene and ethylene, and a second component selected from the group consisting of low density polyethylene, ethylene-vinyl acetate copolymer, acrylate-modified polyethylenes, high density polyethylenes, ethylene-propylene rubber (EPR or EPDM), and blends thereof. The method for producing the composition comprises first blending the components, and then visbreaking the resulting blend. The visbreaking may be carried out in the presence of peroxide concentrations of 50-2,000 ppm, and melt temperatures of 350.degree.-550.degree. F., in a single or twin screw extruder. Thermal visbreaking, at temperatures in excess of 550.degree. F. and the absence of free radial initiators and process or heat stabilizer additives, can also be used.
"Structure and Properties of Rubber Modified Polypropylene Impact Blends,", F. C. Stehling, T. Huff, C. S. Speed, and G. Wissler, Journal of Applied Polymer Science, Vol. 26, pp. 2693-2711 (1981), discloses the dispersion of poly(ethylene-co-propylene) (PEP) rubber and high density polyethylene (HDPE) in polypropylene (PP) blends. Various PP-PEP blends, such as 90-10 , 85-15, and 80-20 L wt.% ratios, and PP-PEP-HDPE blends including 80-10-10, 85-7.5-7.5, and 90-5-5 wt.% ratios, were studied. In such ratios, PEP was dispersed at a discontinuous phase within a continuous phase of PP in the two component blends. In the three component blends, a discontinuous phase of particles of PEP and HDPE was dispersed within a continuous phase of PP; the particles of the discontinuous phase comprised an interior region of HDPE surrounded by an outer layer of PEP.
None of these references discloses or suggests the use of the elastomer compositions disclosed in the COZEWITH et al. patent or applications in such plastic-elastomer blends.